Crankpin grinding apparatus



March 2, 1954 J, A, s 2,670,578

CRANKPIN GRINDING APPARATUS Filed Nov. 12, 1952 f/ VIII/11111111111111111111lll/lllllllll/llllll11111111/ y 2| v I INVENTOR.

Joseph A. Si lIs Patented Mar. 2, 1954 UNITED 'STATES ATENT OFFICE Claims.

The present invention relates to apparatus for grindingr and refinishing the crankpin on a crank- Shaft of an internal combustion engine, or the like, While the crankshaft is in its normal position supported by its main bearings in the engine block..

Grinding and refinishing apparatus that have beenproposed heretofore for the purpose noted have not met with any substantial commercial success due primarily to the complicated and expensive character of the elements involved and to the. diii'iculty of obtaining proper alignment between the crankpin undergoing the operation and its associated cylinder in the engine block.

Accordingly it is a general object of the present invention to provide an improved apparatus for grinding and reiinishing a crankpin as previously noted that positively insures proper alignment between the crankpin and its` cylinder in the engine block.

Another object of the invention is to provide an improved apparatus for grinding and refinishing a crankpin as previously notedwhile the crankpin undergoing the operation is connected by a connecting rod to its piston arranged in its cylinder in the engine block, whereby the guided reciprocatory movement of the connecting rod establishes proper alignment between the crankpin and its cylinder as the operation proceeds.

A further object of the invention is to provide exceedingly simple apparatus for grinding and renishing a crankpin on a crankshaft while the crankshaft is supported by its main bearings in an `engine block and while the crankpin is operatively connected by a connecting rod to its piston arranged in its cylinder in the block.

Further features of the invention pertain to the particular arrangement of the elements. of the apparatus, whereby the above-outlined and additional operating features; thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood byreference. to the following specification taken in. connection with the accompanying drawing. in which:

Figure 1 is an upstanding lateral sectional view of an internal combustion engine of the Lv-head type and incorporating grinding and renishing apparatus embodying the present invvcntion;

Fig. 2 is an enlarged t0n view of the upper hearing member and. upper grinding element cemented ,inthe apparatus shown in Eligi;

Fig. 3 is an enlarged side view of the parts shown in Fig. 2; 1

Fig. 4 is an enlarged bottom view of the lower cap and lower bearing member and lower grinding element incorporated in the apparatus shown in Fig. 1;

Fig. 5 is an enlarged top view of the parts shown in Fig. 4; and

Fig. 6 is an enlarged side View, partly broken away, of the parts shown in Figs. 4 and 5.

Referring now to Fig. 1 of the drawing, there is illustrated a conventional internal combustion engine I0 of the L.head type (Plymouth, 1939) including a block II, a head I2 detachablysecured to the top of the block II, and an oilpan I3 detachably secured to the bottom of the block II, the lower portion of block Il and the oilpan i3 cooperating to dene a crankcase It housing a crankshaftA I5 mounted for rotation upon main bearings, not shown. The block II is provided with six cylinders in which s ix pistons are respectively arranged, one of the cylinders and one of the pistons being respectively indicated at It and Il. The crankshaft I5 is provided with six crankpins respectively aligned with the six cylinders, the crankpin aligned with the cylinder I6 being illustrated at IB. The piston I1 and the crankpin I8 are interconnected by a connecting rod I9, the upper or piston end of the connecting rod I9 being directly connected to the piston Il by a wristpin 20 and the lower or crank end of the connectingA rod I9 terminating in a flange 2l that normally carries an upper bearing member, not shown. Also a bearing cap, not shown, is provided that carries a lower bearing member, not shown, the bearing cap being detachably secured to the iiange 2I by bolts 22, whereby the upper and lower bearing members engage the opposite sides of the crankpin I8 embraced thereby. The head I2 is provided with six domes 23, etc. respectively cooperating with the upper ends of the six cylinders I6, etc.; as well as six intake poppet Valves 24, etc., and six exhaust poppet valves, not shown, that respectively control the cycles of the pistons I1, etc. Finally the head I2 has six threaded holes 25, etc. therein that respectively receive six spark plugs, not shown, that are incorporated in the ignition system of the engine I0.

Now in the event it becomes necessary to regrind or refinish the crankpin I8, the oilpan I3 is removed from the bottom of the block II, followed by the removal of the bearing cap and carried lower bearing member, not shown, and by the remet-e1 0.5. the upper bearing member, not

shown, from the flange 2l. The grinding apparatus, illustrated generally at 30, is then assembled upon the crankpin I8 and the iiange 2I; and thereafter the grinding and refinishing operation is carried out, as explained more fully hereinafter, by rotating the crankshaft I5, while the crankshaft I5 is supported by its main bearings, not shown, in the block II, and while the crankpin I8 is connected by the connecting rod IS to the piston I 1.

More particularly, the apparatus 3i! comprises an upper assembly 3|, shown in Figs. 2 and 3, and a lower assembly 32, shown in Figs. 4 to 6, inclusive. The assembly 3i essentially comprises an upper substantially semi-cylindrical bearing member 33 terminating in two laterally spacedapart and outwardly and oppositely directed flanges 34 having bolt holes 35 formed therein, and carrying two upper grinding elements or pads 36 containing carborundum or other grinding compound. The assembly 32 essentially comprises a lower bearing cap 31 terminating in two laterally spaced-apart bosses 33 having bolt holes 39 formed therein. Also the cap 31 carries a substantially semi-cylindrical lower bearing member 40 arranged in two laterally spacedapart sections and essentially formed of babbitt or other bearing material, as well as a centrally disposed grinding shoe 4I carrying a lower grinding element or pad 42 containing carborundum or other grinding compound. More particularly, the central portion of the cap 3'.' has a longitudinally extending slot 43 formed therein that terminates into a wider longitudinally extending slot 44 formed therein, the sides of the slot 44 being disposed adjacent to the inner ends of the two sections of the bearing member 4B; and the grinding shoe 4I being substantially T-shaped in cross-section, including a stem 45 tting into the slot 43 and a head 46 fitting `into the slot 44. Further two laterally spaced apart threaded openings are formed in the cap 31 that receive -two set screws-41 that project into two laterally spaced apart holes 48 formed in the stem 45 of the grinding shoe 4I, the holes 48 also receiving resilient coil springs 49 surrounding the inner ends of the set screws 41. Thus it will be understood that the springs 49 resiliently bias the grinding shoe 4I inwardly toward thel center of the cap 31, while the set screws 41 accommodate adjustment of the angle between the opposite ends of the grinding shoe 4I and the longitudinal centerline of the cap 31.

In assembling the apparatus 30 upon the crankpin I8 and the iiange 2l, the assembly 3i is placed in the flange 2l (instead of the usual upper bearing member), and the assembly 32 is secured to the flange 2! by the bolts 22 (instead of the usual lower bearing cap). Accordingly, at this time the upper grinding pads 3S, as well as the lower grinding pad 42, directly engage the exterior surface of the crankpin I8; and the bearing cap 31 secures the assemblies 3l and 32 to the crankpin I8 and to the flange 2i; whereby the apparatus 3D, as a whole, is maintained in alignment with respect to the cylinder I6 associated with the crankpin I8. Moreover the springs 49 urge the grinding pad 42 upwardly into firm engagement with the adjacent surface of the crankpin I8; whereby a grinding pressure is maintained between the crankpin I8 and the grinding pads 35 and 42. At this time, the crankshaft I5 is rotated; whereby a grinding action is produced by the grinding elements 3S and 42 upon the exterior surface of the graphpin I8; and the piston I1 is reciprocated in the cylinder I6 by virtue of the operative connection, including the connecting rod I9, between the crankpin I8 and the piston I1. The guided reciprocatory movement of the piston I1 in the cylinder I5 maintains through the connecting rod I9 proper alignment of the apparatus 30 so that the reground or renished surface of the crankpin I8 is in proper alignment with respect to the cylinder IE.

In passing, it is noted that the crankshaft I5 may be rotated by hand or in any suitable manner, such, for example, as by the starter motor normally associated with the engine Il). On the other hand, the spark plug normally associated with the threaded hole 25 in the dome 23 may be removed, and the engine (Il may be run employing the other ve pistons under its own power. In any case, the crankshaft I5 is rotated for the required relatively few revolutions so as to bring about the requiredY and desired grinding action by the apparatus 30 upon the crankpin i8. Ordinarily it is not necessary to assemble the oilpan I3 upon the bottom of the block Ii as there is no damage to the moving parts during the short time interval required in grinding the crankpin I8.

In the foregoing description of the grinding the crankpin IB employing the apparatus 30, it was assumed that the upper bearing member normally carried by the flange 2l of the connecting rod I9 is readily removable therefrom, which is the case in the usual Chrysler engine (Chrysler, DeSoto and Plymouth). However, in :orne General Motors engines (Buick, Oldsmobile, etc.), the upper bearing member is directly babbitted or cast in place in the ange 2l o f the connecting rod I9; whereby in this case, it is necessary to provide in conjunction Awith the apparatus 30, a connecting rod for the particular engine that has the upper bearing element removed therefrom. In this peculiar case, the regular connecting rod I9 is detached from the piston I1 at the wristpin 2U and the alternative connecting rod mentioned is substituted so that the substituted connecting rod may readily receive the assembly 3l, in the manner previously explained. Y j

In connection with the operation of the apparatus 30, it is emphasized that the arrangement of the set screws 41 accommodates adjustment of the angle between the opposite ends of the grinding shoe 4I and the longitudinal centerline of the crankpin I8 so that an original and undesired taper or cone-shape in the outer surface of the erankpin I8 may be removed or eliminated therefrom in the operation of the apparatus 3B. Specifically in this case, the set screw 41 adjacent to the larger end of the crankpin I8 is set tighter than the other set screw 41 adjacent to the smaller end of the crankpin I8 so that the grinding pressure is greater at the larger end of the crankpin I8 in order preferably to grind the larger end of the crankpin I8 so as to remove the undesired taper mentioned.

In view of the foregoing, it is apparent that there has been provided an improved apparatus for grinding or refinishing the crankpin on a crankshaft while the crankshaft is supported in its main bearings in the engine block and while the crankpin undergoing the operation is operatively connected to its piston arranged in its cylinder in the engine block; that is of exceedingly simple construction and arrangement involving only a few quite simple parts. Further,

it will be appreciated that the apparatus is very advantageous as the mere rotation of the crankshaft positively insures that the reground or refinished surface on the crankpin undergoing the operation is positively in alignment with its associated cylinder by virtue of the fact that the guided reciprocatory movement of the connected connecting rod compels the alignment mentioned.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modications as fall within the true spirit and scope of the invention.

What is claimed is:

1. Apparatus for grinding the crankpin on a crankshaft while said crankshaft is supported by its main bearings in an engine block and while said crankpin is operatively connected by a connecting rod to its piston arranged in its cylinder in said block; said apparatus comprising a irst bearing member carried by the crank end of said connecting rod, a cap, a second bearing member carried by said cap and having a longitudinally extending slot formed therein, an elongated grinding element arranged in said slot, means for detachably securing said cap to the crank end of said connecting rod and for clamping said crankpin between said bearing members with said grinding element in engagement with said crankpin, resilient means arranged in said slot between said cap and said grinding element for biasing said grinding element toward said crankpin, the clamping action between the crank end of said connecting rod and said cap producing a grinding pressure between said grinding element and said crankpin and securing the crank end of said connecting rod to said crankpin so that the normal cooperation between said piston and said cylinder establishes proper alignment between said crankpin and said cylinder as the grinding operation is carried out by rotation of said crankshaft, and means for adjustt'ne relative positions of the opposite ends or' said grinding element with respect to the longitudinal centerline of said crankpin.

2. The apparatus set forth in claim l, wherein said adjusting means essentially comprises two set screws arranged in two longitudinally spacedapart threaded holes formed in said cap and extending into the opposite ends of said slot into respective engagements with the opposite ends of said grinding element.

3. The apparatus set forth in claim 2, wherein said resilient means arranged in said slot between said Cap and said grinding element for biasing said grinding element toward said crankpin consists essentially of two coil springs respectively surrounding said two set screws.

4. The apparatus set forth in claim 1, and further comprising a grinding pad carried by said first bearing member and arranged in grinding relation with said crankpin.

5. The apparatus set forth in claim 1, and further comprising two spaoed-apart grinding pads carried by said rst bearing member and both arranged in grinding relation with said crankpin, whereby three spaced-apart grinding actions upon said crankpin are carried out by the rotation of said crankshaft.

JOSEPH A. SILLS.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,370,141 McNicholas Mar. 1, 1921 2,174,231 Postma Sept. 26, 1939 2,290,730 Blazek July 21, 1942 2,444,308 Postma June 29, 1948 2,520,025 Beck Aug. 22, 1950 2,548,445 Postma Apr. 10, 1951 

